Ex vivo evaluation of the influence of cervical preflaring on choice of apical reciprocating file.

The aim of this study was to evaluate the influence of cervical preflaring on the choice of reciprocating file size (Reciproc system) and the difficulty in reaching the working length for instrumentation of molar root canals. A total of 352 human molars were divided into 2 groups of 176 molars each. In the no preflaring (NPF) group, no cervical preflaring was performed. A reciprocating file (R25, R40, or R50) was selected, and instrumentation was performed in accordance with the manufacturer's recommendations. In the preflaring (PF) group, a file was selected, and cervical preflaring was performed with the use of No. 30/.10 or No. 25/.08 orifice shaper instruments. The clinician then selected a new reciprocating file or used the originally selected file to perform the instrumentation as done in the NPF group. Any changes in choice of file after preflaring were documented for the PF group, and the number of insertions required to reach the working length was recorded for both groups. After preflaring, the selected file was changed from R25 to R40 in 20.08% of canals, from R25 to R50 in 0.40% of canals, and from R40 to R50 in 42.14% of canals. After preflaring, 2.88% of the canals with an initial selection of an R50 file required an instrument with a larger diameter for effective preparation. There was a statistically significant difference between the groups for all file size changes (P < 0.001; χ² test). The mean numbers of instrument insertions needed for the NPF and PF groups, respectively, were 4.09 and 2.42 (R25); 3.49 and 2.31 (R40); and 2.70 and 1.81 (R50). There was a statistically significant difference between the groups for all file sizes (P < 0.001; Kruskal-Wallis test). Under the conditions of this study, preflaring enabled a more suitable selection of reciprocating instrument, which, in turn, allowed for fewer insertions of the file up to the working length.

Analysis of Instrumentation Protocols Regarding the Quality of Mesial Canal Preparation in Mandibular Molars: A Micro-computed Tomographic Study.

INTRODUCTION: This study aimed to use micro-computed tomographic imaging to analyze the quality of the endodontic preparation of mesial canals in mandibular molars provided by 3 instrumentation protocols. METHODS: Forty-five extracted mandibular molars with 2 independent mesial canals were selected, and the initial micro-computed tomographic imaging was performed. The initial volume values of the canals were submitted to statistical analysis for paired division. The groups were determined according to the final enlargement of the canal and the working length adopted (ie, G25.06/+1 mm, G35.05/foramen, and G50.01/-1 mm). At the end of each instrumentation sequence, the root canals were scanned and analyzed with regard to the increase in the total and apical volume, centralization, and preparation transportation and the percentage of the total and apical uninstrumented walls. RESULTS: For the intragroup comparison, the Wilcoxon test was used, and for the intergroup analysis, the Kruskal-Wallis and Dunn tests were used (P < .05). In the analysis of the canal total volume, a statistical difference was found between G25.06/+1 mm and the remaining groups (P < .05). In the apical third, a statistical difference was observed between G25.06/+1 mm and G50.01/-1 mm (P < .05). No statistical difference was found between the groups in terms of centralization and transportation of the preparation or in terms of the percentage of the total or apical uninstrumented walls. CONCLUSIONS: The preparation of the mesial canals of mandibular molars up to larger tip files but with a lower taper at 1 mm before the foramen resulted in a larger volume of apical preparation, kept the preparation centralized, and provided safe apical dentin wear without excessive cervical wear.

Avaliação ex vivo da durabilidade de sistemas de instrumentação de NiTi tratados termicamente / Ex-vivo evaluation of the durability of thermally treated NiTi endodontic files

Objetivo: O presente estudo teve como objetivo comparar três sistemas de instrumentação de NiTi, tratados termicamente, quanto ao número de condutos instrumentados até a fratura. Métodos: Foram utilizados 210 molares humanos inferiores e superiores com curvaturas leves a moderadas, comprimentos reais entre 19 e 21 mm e forames apicais até 200µm. Esses foram randomicamente divididos em três grupos de acordo com o sistema de instrumentação utilizado: Reciproc (REC; R25), ProDesign Duo Híbrido (PDH; #25/.01 e #25/.08) e TF Adaptive (TFA; #25/.08). Foram utilizados 5 instrumentos/kits de cada sistema. Registrou-se, então, o número de condutos instrumenta- dos até a fratura e o número de reinserções necessárias até o alcance do comprimento de trabalho. Resultados: A análise estatística apontou diferenças significativas quando comparada a durabilidade dos sistemas, tendo os instrumentos do grupo PDH oferecido os maiores valores (29,2), seguido de REC (21,6) e TFA (15,4) (p<0,05). Quanto ao número de reinserções, o sistema TFA foi o que necessitou do menor número de reinserções (p<0,05). Conclusão: Nas condições do estudo, pode-se concluir que o sistema ProDesign Duo Híbrido foi o mais durável; ainda que o sistema TF Adaptive tenha alcançado o comprimento de trabalho com maior facilidade

Objective: The present study compared three systems of thermally treated NiTi endodontic files regarding their achieved number of prepared root canals before fracture. Methods: Two hundred and ten slightly and moderately curved upper and lower molars with actual length ranging from 19 to 21 mm and apex foramens diameters up to 200 µm were used. The sample was allotted to three groups according to the instrumentation system in use: Reciproc (REC; R25), ProDesign Duo Hybrid (PDH; #25/.01 and #25/.08), and TF Adaptive (TFA; #25/.08). Five instruments/kits of each system were used. Then, it was registered the number of root canals prepared until the instrument fractured and the number of reinsertions needed until the working length was achieved. Results: The statistical analysis showed significant differences among the durability of the three systems, being the instruments of group PDH the ones that yielded higher reuses (29.2) followed by groups REC (21.6), and TFA (15.4) (P < .05). Regarding the number of insertions, the TFA system was the one that needed the lowest number of reinsertions (P < .05). Conclusion: Under this study conditions, ProDesign Duo Hybrid was the most durable system, whereas TF Adaptive system was the one that most easily achieved the working length.

Clorexidina: uma nova proposta na Endodontia / Chlorhexidine: a novel perspective in Endodontics

Introdução: a clorexidina demonstra resultados efetivos na Endodontia como uma substância de irrigação ou como medicação intracanal. Objetivo: o objetivo do presente estudo foi revisar a literatura sobre as propriedades da clorexidina, enfatizando novos achados sobre o uso dessa substância como uma medicação intracanal e como uma substância de irrigação. Métodos: foi realizada uma pesquisa nos bancos de dados online Bireme e Google Scholar, usando como palavras-chave as substâncias de irrigação clorexidina e hipoclorito de sódio, restringindo a pesquisa ao período de 2000 a agosto de 2015. Resultados: verificou-se que a clorexidina apresenta uma ampla gama de propriedades que aumentam seu potencial como uma substância de irrigação, quando comparada ao hipoclorito de sódio, como: efeito antimicrobiano, substantividade e baixa toxicidade. Devido a todas as características mencionadas anteriormente, a clorexidina tem sido considerada uma perspectiva inovadora no tratamento de infecções endodônticas, embora o hipoclorito de sódio ainda seja a substância de irrigação de escolha entre os clínicos. Conclusão: esse estudo demonstrou que a clorexidina é uma alternativa efetiva para a desinfecção e o tratamento dos canais radiculares (AU).

Introduction: Chlorhexidine demonstrates effective results in endodontics as an irrigation substance, or as an intra-canal medication. Aim: The aim of this study is to review the literature about the properties of chlorhexidine, emphasizing new findings about the use of this substance as an intra-canal medication, and as an irrigation substance. Methods: Thus, a search was performed on the online databases Bireme and Google Scholar using the keywords irrigation substances, chlorhexidine, and sodium hypochlorite, restricting the search to the period from the year of 2000 to August of 2015. Results: It was found that Chlorhexidine presents a wide range of properties that enhance its potential as an irrigation substance when compared to sodium hypochlorite, such as antimicrobial effect, substantivity, and low toxicity. Due to all the before mentioned characteristics, chlorhexidine has been considered a novel perspective in the treatmentof endodontic infections, even though sodium hypochlorite is still the irrigation substance of choice among clinicians. Conclusion: Therefore, this study demonstrated that chlorhexidine is an effective alternative to the disinfection and treatment of the root canals (AU).